/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.api.java.typeutils;

import org.apache.flink.annotation.Public;
import org.apache.flink.annotation.PublicEvolving;
import org.apache.flink.api.common.ExecutionConfig;
import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.api.common.typeutils.base.GenericArraySerializer;

import java.lang.reflect.Array;

import static org.apache.flink.util.Preconditions.checkArgument;
import static org.apache.flink.util.Preconditions.checkNotNull;

@Public
public class ObjectArrayTypeInfo<T, C> extends TypeInformation<T> {

    private static final long serialVersionUID = 1L;

    private final Class<T> arrayType;
    private final TypeInformation<C> componentInfo;

    private ObjectArrayTypeInfo(Class<T> arrayType, TypeInformation<C> componentInfo) {
        this.arrayType = checkNotNull(arrayType);
        this.componentInfo = checkNotNull(componentInfo);
    }

    // --------------------------------------------------------------------------------------------

    @Override
    @PublicEvolving
    public boolean isBasicType() {
        return false;
    }

    @Override
    @PublicEvolving
    public boolean isTupleType() {
        return false;
    }

    @Override
    @PublicEvolving
    public int getArity() {
        return 1;
    }

    @Override
    @PublicEvolving
    public int getTotalFields() {
        return 1;
    }

    @SuppressWarnings("unchecked")
    @Override
    @PublicEvolving
    public Class<T> getTypeClass() {
        return arrayType;
    }

    @PublicEvolving
    public TypeInformation<C> getComponentInfo() {
        return componentInfo;
    }

    @Override
    @PublicEvolving
    public boolean isKeyType() {
        return false;
    }

    @SuppressWarnings("unchecked")
    @Override
    @PublicEvolving
    public TypeSerializer<T> createSerializer(ExecutionConfig executionConfig) {
        return (TypeSerializer<T>)
                new GenericArraySerializer<C>(
                        componentInfo.getTypeClass(),
                        componentInfo.createSerializer(executionConfig));
    }

    @Override
    public String toString() {
        return this.getClass().getSimpleName() + "<" + this.componentInfo + ">";
    }

    @Override
    public boolean equals(Object obj) {
        if (obj instanceof ObjectArrayTypeInfo) {
            @SuppressWarnings("unchecked")
            ObjectArrayTypeInfo<T, C> objectArrayTypeInfo = (ObjectArrayTypeInfo<T, C>) obj;

            return objectArrayTypeInfo.canEqual(this)
                    && arrayType == objectArrayTypeInfo.arrayType
                    && componentInfo.equals(objectArrayTypeInfo.componentInfo);
        } else {
            return false;
        }
    }

    @Override
    public boolean canEqual(Object obj) {
        return obj instanceof ObjectArrayTypeInfo;
    }

    @Override
    public int hashCode() {
        return 31 * this.arrayType.hashCode() + this.componentInfo.hashCode();
    }

    // --------------------------------------------------------------------------------------------

    @PublicEvolving
    public static <T, C> ObjectArrayTypeInfo<T, C> getInfoFor(
            Class<T> arrayClass, TypeInformation<C> componentInfo) {
        checkNotNull(arrayClass);
        checkNotNull(componentInfo);
        checkArgument(arrayClass.isArray(), "Class " + arrayClass + " must be an array.");

        return new ObjectArrayTypeInfo<T, C>(arrayClass, componentInfo);
    }

    /**
     * Creates a new {@link org.apache.flink.api.java.typeutils.ObjectArrayTypeInfo} from a {@link
     * TypeInformation} for the component type.
     *
     * <p>This must be used in cases where the complete type of the array is not available as a
     * {@link java.lang.reflect.Type} or {@link java.lang.Class}.
     */
    @SuppressWarnings("unchecked")
    @PublicEvolving
    public static <T, C> ObjectArrayTypeInfo<T, C> getInfoFor(TypeInformation<C> componentInfo) {
        checkNotNull(componentInfo);

        return new ObjectArrayTypeInfo<T, C>(
                (Class<T>) Array.newInstance(componentInfo.getTypeClass(), 0).getClass(),
                componentInfo);
    }
}
